/*
 * FreeRTOS Kernel V10.4.1
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 * 1 tab == 4 spaces!
 */

/*
 * A sample implementation of pvPortMalloc() that allows the heap to be defined
 * across multiple non-contigous blocks and combines (coalescences) adjacent
 * memory blocks as they are freed.
 *
 * See heap_1.c, heap_2.c, heap_3.c and heap_4.c for alternative
 * implementations, and the memory management pages of https://www.FreeRTOS.org
 * for more information.
 *
 * Usage notes:
 *
 * vPortDefineHeapRegions() ***must*** be called before pvPortMalloc().
 * pvPortMalloc() will be called if any task objects (tasks, queues, event
 * groups, etc.) are created, therefore vPortDefineHeapRegions() ***must*** be
 * called before any other objects are defined.
 *
 * vPortDefineHeapRegions() takes a single parameter.  The parameter is an array
 * of HeapRegion_t structures.  HeapRegion_t is defined in portable.h as
 *
 * typedef struct HeapRegion
 * {
 *	uint8_t *pucStartAddress; << Start address of a block of memory that will be part of the heap.
 *	size_t xSizeInBytes;	  << Size of the block of memory.
 * } HeapRegion_t;
 *
 * The array is terminated using a NULL zero sized region definition, and the
 * memory regions defined in the array ***must*** appear in address order from
 * low address to high address.  So the following is a valid example of how
 * to use the function.
 *
 * HeapRegion_t xHeapRegions[] =
 * {
 *  { ( uint8_t * ) 0x80000000UL, 0x10000 }, << Defines a block of 0x10000 bytes starting at address 0x80000000
 *  { ( uint8_t * ) 0x90000000UL, 0xa0000 }, << Defines a block of 0xa0000 bytes starting at address of 0x90000000
 *  { NULL, 0 }                << Terminates the array.
 * };
 *
 * vPortDefineHeapRegions( xHeapRegions ); << Pass the array into vPortDefineHeapRegions().
 *
 * Note 0x80000000 is the lower address so appears in the array first.
 *
 */
#include <stdlib.h>

/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
 * all the API functions to use the MPU wrappers.  That should only be done when
 * task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#include "FreeRTOS.h"
#include "task.h"

#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#if (configSUPPORT_DYNAMIC_ALLOCATION == 0)
#error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
#endif

/* Block sizes must not get too small. */
#define heapMINIMUM_BLOCK_SIZE ((size_t)(xHeapStructSize << 1))

/* Assumes 8bit bytes! */
#define heapBITS_PER_BYTE ((size_t)8)

/* Define the linked list structure.  This is used to link free blocks in order
 * of their memory address. */
typedef struct A_BLOCK_LINK {
  struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */
  size_t               xBlockSize;      /*<< The size of the free block. */
} BlockLink_t;

/*-----------------------------------------------------------*/

/*
 * Inserts a block of memory that is being freed into the correct position in
 * the list of free memory blocks.  The block being freed will be merged with
 * the block in front it and/or the block behind it if the memory blocks are
 * adjacent to each other.
 */
static void prvInsertBlockIntoFreeList(BlockLink_t *pxBlockToInsert);

/*-----------------------------------------------------------*/

/* The size of the structure placed at the beginning of each allocated memory
 * block must by correctly byte aligned. */
static const size_t xHeapStructSize = (sizeof(BlockLink_t) + ((size_t)(portBYTE_ALIGNMENT - 1))) & ~((size_t)portBYTE_ALIGNMENT_MASK);

/* Create a couple of list links to mark the start and end of the list. */
static BlockLink_t xStart, *pxEnd = NULL;

/* Keeps track of the number of calls to allocate and free memory as well as the
 * number of free bytes remaining, but says nothing about fragmentation. */
static size_t xFreeBytesRemaining            = 0U;
static size_t xMinimumEverFreeBytesRemaining = 0U;
static size_t xNumberOfSuccessfulAllocations = 0;
static size_t xNumberOfSuccessfulFrees       = 0;

/* Gets set to the top bit of an size_t type.  When this bit in the xBlockSize
 * member of an BlockLink_t structure is set then the block belongs to the
 * application.  When the bit is free the block is still part of the free heap
 * space. */
static size_t xBlockAllocatedBit = 0;

/*-----------------------------------------------------------*/

void *pvPortMalloc(size_t xWantedSize) {
  BlockLink_t *pxBlock, *pxPreviousBlock, *pxNewBlockLink;
  void        *pvReturn = NULL;

  /* The heap must be initialised before the first call to
   * prvPortMalloc(). */
  configASSERT(pxEnd);

  vTaskSuspendAll();
  {
    /* Check the requested block size is not so large that the top bit is
     * set.  The top bit of the block size member of the BlockLink_t structure
     * is used to determine who owns the block - the application or the
     * kernel, so it must be free. */
    if ((xWantedSize & xBlockAllocatedBit) == 0) {
      /* The wanted size is increased so it can contain a BlockLink_t
       * structure in addition to the requested amount of bytes. */
      if (xWantedSize > 0) {
        xWantedSize += xHeapStructSize;

        /* Ensure that blocks are always aligned to the required number
         * of bytes. */
        if ((xWantedSize & portBYTE_ALIGNMENT_MASK) != 0x00) {
          /* Byte alignment required. */
          xWantedSize += (portBYTE_ALIGNMENT - (xWantedSize & portBYTE_ALIGNMENT_MASK));
        } else {
          mtCOVERAGE_TEST_MARKER();
        }
      } else {
        mtCOVERAGE_TEST_MARKER();
      }

      if ((xWantedSize > 0) && (xWantedSize <= xFreeBytesRemaining)) {
        /* Traverse the list from the start	(lowest address) block until
         * one	of adequate size is found. */
        pxPreviousBlock = &xStart;
        pxBlock         = xStart.pxNextFreeBlock;

        while ((pxBlock->xBlockSize < xWantedSize) && (pxBlock->pxNextFreeBlock != NULL)) {
          pxPreviousBlock = pxBlock;
          pxBlock         = pxBlock->pxNextFreeBlock;
        }

        /* If the end marker was reached then a block of adequate size
         * was	not found. */
        if (pxBlock != pxEnd) {
          /* Return the memory space pointed to - jumping over the
           * BlockLink_t structure at its start. */
          pvReturn = (void *)(((uint8_t *)pxPreviousBlock->pxNextFreeBlock) + xHeapStructSize);

          /* This block is being returned for use so must be taken out
           * of the list of free blocks. */
          pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;

          /* If the block is larger than required it can be split into
           * two. */
          if ((pxBlock->xBlockSize - xWantedSize) > heapMINIMUM_BLOCK_SIZE) {
            /* This block is to be split into two.  Create a new
             * block following the number of bytes requested. The void
             * cast is used to prevent byte alignment warnings from the
             * compiler. */
            pxNewBlockLink = (void *)(((uint8_t *)pxBlock) + xWantedSize);

            /* Calculate the sizes of two blocks split from the
             * single block. */
            pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
            pxBlock->xBlockSize        = xWantedSize;

            /* Insert the new block into the list of free blocks. */
            prvInsertBlockIntoFreeList((pxNewBlockLink));
          } else {
            mtCOVERAGE_TEST_MARKER();
          }

          xFreeBytesRemaining -= pxBlock->xBlockSize;

          if (xFreeBytesRemaining < xMinimumEverFreeBytesRemaining) {
            xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
          } else {
            mtCOVERAGE_TEST_MARKER();
          }

          /* The block is being returned - it is allocated and owned
           * by the application and has no "next" block. */
          pxBlock->xBlockSize |= xBlockAllocatedBit;
          pxBlock->pxNextFreeBlock = NULL;
          xNumberOfSuccessfulAllocations++;
        } else {
          mtCOVERAGE_TEST_MARKER();
        }
      } else {
        mtCOVERAGE_TEST_MARKER();
      }
    } else {
      mtCOVERAGE_TEST_MARKER();
    }

    traceMALLOC(pvReturn, xWantedSize);
  }
  (void)xTaskResumeAll();

#if (configUSE_MALLOC_FAILED_HOOK == 1)
  {
    if (pvReturn == NULL) {
      extern void vApplicationMallocFailedHook(void);
      vApplicationMallocFailedHook();
    } else {
      mtCOVERAGE_TEST_MARKER();
    }
  }
#endif /* if ( configUSE_MALLOC_FAILED_HOOK == 1 ) */

  return pvReturn;
}
/*-----------------------------------------------------------*/

void vPortFree(void *pv) {
  uint8_t     *puc = (uint8_t *)pv;
  BlockLink_t *pxLink;

  if (pv != NULL) {
    /* The memory being freed will have an BlockLink_t structure immediately
     * before it. */
    puc -= xHeapStructSize;

    /* This casting is to keep the compiler from issuing warnings. */
    pxLink = (void *)puc;

    /* Check the block is actually allocated. */
    configASSERT((pxLink->xBlockSize & xBlockAllocatedBit) != 0);
    configASSERT(pxLink->pxNextFreeBlock == NULL);

    if ((pxLink->xBlockSize & xBlockAllocatedBit) != 0) {
      if (pxLink->pxNextFreeBlock == NULL) {
        /* The block is being returned to the heap - it is no longer
         * allocated. */
        pxLink->xBlockSize &= ~xBlockAllocatedBit;

        vTaskSuspendAll();
        {
          /* Add this block to the list of free blocks. */
          xFreeBytesRemaining += pxLink->xBlockSize;
          traceFREE(pv, pxLink->xBlockSize);
          prvInsertBlockIntoFreeList(((BlockLink_t *)pxLink));
          xNumberOfSuccessfulFrees++;
        }
        (void)xTaskResumeAll();
      } else {
        mtCOVERAGE_TEST_MARKER();
      }
    } else {
      mtCOVERAGE_TEST_MARKER();
    }
  }
}
/*-----------------------------------------------------------*/

size_t xPortGetFreeHeapSize(void) { return xFreeBytesRemaining; }
/*-----------------------------------------------------------*/

size_t xPortGetMinimumEverFreeHeapSize(void) { return xMinimumEverFreeBytesRemaining; }
/*-----------------------------------------------------------*/

static void prvInsertBlockIntoFreeList(BlockLink_t *pxBlockToInsert) {
  BlockLink_t *pxIterator;
  uint8_t     *puc;

  /* Iterate through the list until a block is found that has a higher address
   * than the block being inserted. */
  for (pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock) {
    /* Nothing to do here, just iterate to the right position. */
  }

  /* Do the block being inserted, and the block it is being inserted after
   * make a contiguous block of memory? */
  puc = (uint8_t *)pxIterator;

  if ((puc + pxIterator->xBlockSize) == (uint8_t *)pxBlockToInsert) {
    pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
    pxBlockToInsert = pxIterator;
  } else {
    mtCOVERAGE_TEST_MARKER();
  }

  /* Do the block being inserted, and the block it is being inserted before
   * make a contiguous block of memory? */
  puc = (uint8_t *)pxBlockToInsert;

  if ((puc + pxBlockToInsert->xBlockSize) == (uint8_t *)pxIterator->pxNextFreeBlock) {
    if (pxIterator->pxNextFreeBlock != pxEnd) {
      /* Form one big block from the two blocks. */
      pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
      pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
    } else {
      pxBlockToInsert->pxNextFreeBlock = pxEnd;
    }
  } else {
    pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
  }

  /* If the block being inserted plugged a gab, so was merged with the block
   * before and the block after, then it's pxNextFreeBlock pointer will have
   * already been set, and should not be set here as that would make it point
   * to itself. */
  if (pxIterator != pxBlockToInsert) {
    pxIterator->pxNextFreeBlock = pxBlockToInsert;
  } else {
    mtCOVERAGE_TEST_MARKER();
  }
}
/*-----------------------------------------------------------*/

void vPortDefineHeapRegions(const HeapRegion_t *const pxHeapRegions) {
  BlockLink_t        *pxFirstFreeBlockInRegion = NULL, *pxPreviousFreeBlock;
  size_t              xAlignedHeap;
  size_t              xTotalRegionSize, xTotalHeapSize = 0;
  BaseType_t          xDefinedRegions = 0;
  size_t              xAddress;
  const HeapRegion_t *pxHeapRegion;

  /* Can only call once! */
  configASSERT(pxEnd == NULL);

  pxHeapRegion = &(pxHeapRegions[xDefinedRegions]);

  while (pxHeapRegion->xSizeInBytes > 0) {
    xTotalRegionSize = pxHeapRegion->xSizeInBytes;

    /* Ensure the heap region starts on a correctly aligned boundary. */
    xAddress = (size_t)pxHeapRegion->pucStartAddress;

    if ((xAddress & portBYTE_ALIGNMENT_MASK) != 0) {
      xAddress += (portBYTE_ALIGNMENT - 1);
      xAddress &= ~portBYTE_ALIGNMENT_MASK;

      /* Adjust the size for the bytes lost to alignment. */
      xTotalRegionSize -= xAddress - (size_t)pxHeapRegion->pucStartAddress;
    }

    xAlignedHeap = xAddress;

    /* Set xStart if it has not already been set. */
    if (xDefinedRegions == 0) {
      /* xStart is used to hold a pointer to the first item in the list of
       *  free blocks.  The void cast is used to prevent compiler warnings. */
      xStart.pxNextFreeBlock = (BlockLink_t *)xAlignedHeap;
      xStart.xBlockSize      = (size_t)0;
    } else {
      /* Should only get here if one region has already been added to the
       * heap. */
      configASSERT(pxEnd != NULL);

      /* Check blocks are passed in with increasing start addresses. */
      configASSERT(xAddress > (size_t)pxEnd);
    }

    /* Remember the location of the end marker in the previous region, if
     * any. */
    pxPreviousFreeBlock = pxEnd;

    /* pxEnd is used to mark the end of the list of free blocks and is
     * inserted at the end of the region space. */
    xAddress = xAlignedHeap + xTotalRegionSize;
    xAddress -= xHeapStructSize;
    xAddress &= ~portBYTE_ALIGNMENT_MASK;

    pxEnd                  = (BlockLink_t *)xAddress;
    pxEnd->xBlockSize      = 0;
    pxEnd->pxNextFreeBlock = NULL;

    /* To start with there is a single free block in this region that is
     * sized to take up the entire heap region minus the space taken by the
     * free block structure. */
    pxFirstFreeBlockInRegion                  = (BlockLink_t *)xAlignedHeap;
    pxFirstFreeBlockInRegion->xBlockSize      = xAddress - (size_t)pxFirstFreeBlockInRegion;
    pxFirstFreeBlockInRegion->pxNextFreeBlock = pxEnd;

    /* If this is not the first region that makes up the entire heap space
     * then link the previous region to this region. */
    if (pxPreviousFreeBlock != NULL) {
      pxPreviousFreeBlock->pxNextFreeBlock = pxFirstFreeBlockInRegion;
    }

    xTotalHeapSize += pxFirstFreeBlockInRegion->xBlockSize;

    /* Move onto the next HeapRegion_t structure. */
    xDefinedRegions++;
    pxHeapRegion = &(pxHeapRegions[xDefinedRegions]);
  }

  xMinimumEverFreeBytesRemaining = xTotalHeapSize;
  xFreeBytesRemaining            = xTotalHeapSize;

  /* Check something was actually defined before it is accessed. */
  configASSERT(xTotalHeapSize);

  /* Work out the position of the top bit in a size_t variable. */
  xBlockAllocatedBit = ((size_t)1) << ((sizeof(size_t) * heapBITS_PER_BYTE) - 1);
}
/*-----------------------------------------------------------*/

void vPortGetHeapStats(HeapStats_t *pxHeapStats) {
  BlockLink_t *pxBlock;
  size_t       xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */

  vTaskSuspendAll();
  {
    pxBlock = xStart.pxNextFreeBlock;

    /* pxBlock will be NULL if the heap has not been initialised.  The heap
     * is initialised automatically when the first allocation is made. */
    if (pxBlock != NULL) {
      do {
        /* Increment the number of blocks and record the largest block seen
         * so far. */
        xBlocks++;

        if (pxBlock->xBlockSize > xMaxSize) {
          xMaxSize = pxBlock->xBlockSize;
        }

        /* Heap five will have a zero sized block at the end of each
         * each region - the block is only used to link to the next
         * heap region so it not a real block. */
        if (pxBlock->xBlockSize != 0) {
          if (pxBlock->xBlockSize < xMinSize) {
            xMinSize = pxBlock->xBlockSize;
          }
        }

        /* Move to the next block in the chain until the last block is
         * reached. */
        pxBlock = pxBlock->pxNextFreeBlock;
      } while (pxBlock != pxEnd);
    }
  }
  (void)xTaskResumeAll();

  pxHeapStats->xSizeOfLargestFreeBlockInBytes  = xMaxSize;
  pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;
  pxHeapStats->xNumberOfFreeBlocks             = xBlocks;

  taskENTER_CRITICAL();
  {
    pxHeapStats->xAvailableHeapSpaceInBytes     = xFreeBytesRemaining;
    pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;
    pxHeapStats->xNumberOfSuccessfulFrees       = xNumberOfSuccessfulFrees;
    pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;
  }
  taskEXIT_CRITICAL();
}
